It's been called the great Midwest test, a delegate jackpot, the crown jewel in "Super Tuesday 2." Of the four states voting Tuesday – including Mississippi, Idaho, and Hawaii – all eyes are on Michigan. The Great Lakes State is a bellwether: How candidates perform there may offer crucial clues for the rest of the race.

Michigan offers three important tests for candidates, especially Republicans:

It is the first big industrial state to hold a primary. That offers a key test for candidates' economic messages, which is one of the components to winning in a general election. It is also an area in which Donald Trump excels.

It is a solidly Midwestern state that will test candidates' durability in that region, possibly slowing the rise of Sen. Ted Cruz of Texas and giving Ohio Gov. John Kasich a boost.

Finally, as a blue state, Michigan may offer clues as to how candidates will perform in upcoming Democratic-leaning states, like New York, California, and New Jersey, and whether their messages can gain traction outside of traditionally red states.

Currently, Mr. Trump and Hillary Clinton are favored to win in Michigan. But on the GOP side, vote margins and who wins the No. 2 spot will provide clues about the anti-Trump crowd.

Michigan offers the biggest delegate count Tuesday: 150 GOP delegates and 179 Democratic delegates. That offers front-runners like Trump and Mrs. Clinton a chance to solidify their leads and rack up enough delegates to make their nominations appear inevitable. And it offers rivals, like Cruz and Kasich, a chance to catch up.

But Michigan isn't necessarily winner-take-all. On either side, a candidate must receive at least 15 percent of the vote to get any delegates. And on the Republican side, any candidate who receives more than half the vote will get all of the state's delegates. That benefits front-runners like Trump and Clinton, and could hurt weaker candidates like Sen. Marco Rubio, and possibly Kasich, who may not meet the threshold.

The Michigan primary is especially important for each of the GOP candidates. Trump is looking to cement his lead with a decisive win. Cruz is looking to cut into the billionaire's margin and assert himself as the only viable Trump alternative. And Kasich has spent considerable time and money campaigning in Michigan and wants to siphon away some of Senator Rubio's voters – upscale, suburban Republicans.

But the Great Lakes contest offers perhaps the greatest test for Trump. He's promised to put Democratic-leaning industrial states like Michigan into play for Republicans. Michigan is a once-solid Republican state that has supported Democrats in the past six presidential elections, as the New York Times reported.

Winning blue-collar white voters, who make up much of Michigan's electorate and Trump's base, is at the core of his strategy to convert Democratic-leaning Rust Belt states into the red column.

A “normal Republican cannot think of bringing in Michigan, and if you don’t bring in Michigan, it’s tough. You have a very narrow road," Trump said at Macomb Community College in Michigan. “But I’m going to bring in places like Michigan,” he pledged.

If he can, he will have a strong argument that he can do that elsewhere – and in a general election.